GI Hot-Road

XR-311 GI Hot-Rod

Author of this Story: Jim Allen

For many years the old slow Jeep was just fine for the U.S. Army. But somewhere along the line they decided they wanted faster tactical vehicles. Along the way, they created new terminology for a vehicle that did not yet exist; the high mobility combat vehicle. That definition has changed a bit over the years, but back then it was for a rig that could haul butt into combat, have a quick look, maybe deliver a punch and then haul butt back out. It was capable of nearly any terrain and had a long range. All this transformed into the 1970 FMC- XR311.
      The Army focused a great deal of attention on the small numbers of prototype XR311s built in various configurations from 1970 to 1978. FMC (Food Machinery Corporation) was into military contracts back in those days and they came up with a vehicle that nearly any four-wheeler would love to own.
      The XR311 was built from the ground up for speed. It took many design ideas from the desert racing dune buggies of the day. In fact, many Army papers of the time referred to it as "an oversized dune buggy." Its backbone was a tubular frame that incorporated a passenger area safety cage. It had a long travel, independent suspension front and rear, full-time four-wheel drive, automatic transmission and a rear mounted Mopar 360 or 318cid four-barrel carburetor V8.
      The tranny was the famous Chrysler Torqueflite 727 that was most often mated to a BW 1339 full-time 4-WD, chain drive t-case (AKA "Quadra-Trac"). It was not fitted with the detachable low-range box, but the center diff could be manually locked. Another variant had an FMC-built t-case that featured a Detroit Locker as a center diff. Both differentials were Dana 44 IFS models with 3.73:1 ratios, similar to those used in Corvettes. Trac-Lok limited slips were fitted at both ends. The independent suspension CV axles were identical to the front-wheel drive Olds Toronado and the suspension was a heavier duty version of the Olds setup. Eleven-inch disc brakes were mounted at all four corners.
      Both 318s and 360s were fitted to the prototypes, but the smaller engine was more common. They used 4-bbl manifolds with specially modified Holley 600cfm dual feed carbs. Power for the 318 was rated at 187 net and torque was rated at 252 net lbs-ft at 3800rpm. A remote, high capacity air filter filtered out desert sand. A standard military 24-volt electrical system was used and the radiator was at the rear of the vehicle. Performance was fairly astounding for this 4,400 pound combat rig. Top speed was listed as either 80 or 90mph. It could do 0-60 in either 10.6 or 12 seconds, depending on whether it had a 360 or a 318. With 30 gallons of fuel it could go 300 miles on a tank. It could carry an extra 10 gallons in cans at the rear. It was rated to ford water 30 inches deep, traverse side slopes at 50 degrees and had 11 inches of ground clearance under its totally flat belly pan. Thor T-200, 8,000 pound electric winches were mounted on most of the prototypes.
      Several versions were built, including a recon vehicle that mounted a .50 cal Browning heavy machine gun, an Anti-Armor vehicle that mounted either a TOW missile or a 106mm recoilless rifle, a Combat Control rig with high-tech radios and a Convoy Escort rig. The later models could also be fitted with a Crew Armor Kit that utilized special aluminum armor to stop small arms bullets

The FMC XR-311 was built in three basic evolutions, the early square headlight model, of which just one or two were made in 1969-70, the so-called "shrouded headlight" version made till 1974 and the last type, made to at least 1978. The latter had a slightly different front end and open headlights protected by guards. Of the last two types, an unknown but fairly large number were made. There are indications that as many as 16 were built. At least one late prototype was fitted with a front mounted, air-cooled, Deutz V8 diesel.
This survivor below is a "shrouded headlight" version from 1971. Its one of a handful of surviving units in the hands of military collectors.
If the look this rig reminds you of something, the word "Hummer" should jog your memory. The original HUMMWV (High Mobility Multipurpose Wheeled Vehicle) of the early '80s, now known in the military as the HUMVEE, can trace it's roots to the early 1970s, and the FMC-built XR311.

Late in the 1970s, both Teledyne and AM General fielded entrants similar to the FMC unit in a program that eventually became the HUMVEE, and even later the civilian Hummer. The Teledyne model became the Lamborghini Cheetah that mounted a V-12 engine.

"This FMC-Built Rig Was the Granddaddy of the Hummer"

The interior features seating for three. Note the original Simpson harnesses. The windshield is removable and can be carried in a rack in front of the passenger. A canvas top was available for rain protection. The ring mount is designed for .50 cal. or 7.62mm machine guns and behind the seats can be seen storage for 600 rounds of machine gun ammo.

End

Return to XR311 main page.